We wish to analyze the repertoire of T cells that trigger autoimmune insulitis in NOD mice. We will then use this information in attempts to identify the antigen(s) involved and to modulate the effects of this disease. In particular, with the observation that Pgp-1 marker on T-cells can be induced upon stimulation, we will enrich for islet-specific T cells from early NOD lymph nodes and islet cells infiltrates using the surface marker, Pgp-1. We will determine the TCR alpha and beta gene usage in these T-cells at a single cell level using PCR, and generate Jurkat transfectants that have the same alpha and beta TCR genes, thus the same specificity as the original T-cells they derived from. such transfectants will be very important in identifying early islet antigens. We also will use information about these early islet cell specific T cells to make soluble TCR proteins to generate monoclonal antibodies to aid in the identification and isolation of such cells, and for therapeutic purposes. The soluble TCR protein(s) and peptides derived from its sequences can also be used as part of a vaccination strategy to ameliorate the disease. We hope that this work will contribute to a critical test of the hypothesis that a limited number of T cell specificities triggers diabetes in the NOD model and that this information and the reagents generated will aid efforts to combat its human counterpart, juvenile onset diabetes.